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Why Is My Thermostat Working, but My Heater Isn’t?

Why Is My Thermostat Working, but My Heater Isn’t?

We all know what it’s like when Los Angeles gets its first chill of the season. In a city defined by warm, wonderful weather, a chilly day can throw everything off. When it happens, we all want a nice warm home to go back to. But what happens when your thermostat is working, but your heater isn’t?

(Quick aside: We normally refer to the heater as the furnace, but in this post, we will use heater and furnace interchangeably.)

Technical Problems that Stop Furnaces from Producing Heat

One of the best things about modern furnaces is that they come with many more safety switches and triggers than older models. However, this can cause a lot of confusion.

Safety switches can be triggered by a furnace that’s too hot, carbon monoxide leak, excess pressure in the furnace, and gas leaks. When a safety switch is triggered, your furnace can’t turn on unless reset by an HVAC professional.

When this happens, your thermostat can be fully functional. However, your heater won’t.

Whatever the issue may be, it’s time to call an HVAC professional when your thermostat is working but your furnace isn’t making any heat.

Thermostat Working, but Heater Isn’t, could be the Gas.

A good majority of furnaces in the United States use gas to run. Most homes have a line that brings in natural gas from a city supply. This natural gas goes into more than your furnace, it also helps with appliances like the stove and clothing dryer.

In addition to gas, air systems also need electricity and water. There are times when we’ve gone to a house and only needed to reset the power breaker.

Another reason why your thermostat is working, but the heater isn’t could be because of a stuck gas valve. In the same vein, we’ve seen homes where the control board can’t communicate with the thermostat.

When this happens, the furnace is ready to heat the home, but a flame can’t ignite. To test this, if you have a gas stove, go to your kitchen, and try to light a burner. If a flame ignites, the problem isn’t the gas line. However, no flame on the stove means you probably have a broken gas line.

The Furnace Needs Maintenance Work Done

If there’s one thing, we wish every homeowner would do, it’s to schedule yearly maintenance for their furnace and air conditioner.

When conducting a furnace tune-up, an Adeedo HVAC tech will go over every part of your system. They’ll check it, test it, then clean it, and put it all back together. We believe that every furnace is unique and needs unique care.

We see too many homeowners who forego routine maintenance and only call us out when something catastrophic has happened. Twice yearly tune-ups catch small problems before they become big headaches.

Did You Forget to Change Your Air Filter?

After tune-ups, the next best thing you can do for your system is to routinely check and change the air filter. No matter what type of air filter you have in your system, it will get old and need to be replaced.

Over time and with use, all air filters get full. It means they’re doing their job correctly. However, when an air filter is too full, it can block airflow.

When an air filter is somewhat clean, temperature treated air can glide right though it. This makes it easy for your home to get nice and toasty. The opposite it true with an overfull filter.

Your furnace will try to push heat treated air through the clogged filter, but the filter blocks airflow and makes it hard for anything to get through.

This makes it so your thermostat is on, but there’s no warm air coming from your furnace. Additionally, a clogged air filter can cause your utility bill to go sky high because your system is forced to work twice as hard to make the same amount of air.

Is Your Furnace Short Cycling?

Your furnace is constantly running on a cycle. The cycle starts when the thermostat tells the HVAC system to start producing warm air. Then, the cycle stops when your home has reached the desired temperature.

A typical cycle usually lasts between 15 and 20 minutes. Sometimes a furnace will short cycle. For example, the cycle will stop when either before the house is fully heated, or the house is heating too quickly and losing air just as fast.

Your furnace will short cycle if:

  1. The furnace itself is overheating
  2. The air filter is too dirty and too full of debris
  3. Your flame sensor isn’t working
  4. The thermostat is in the wrong spot
  5. Your Furnace is too big for your home

For the best furnace maintenance in Los Angeles County, reach out to the experts at Adeedo. Call the number at the top of the screen or click here to book online.